* {
  margin: 0;
  padding: 0; }

body {
  font-size: 16px; }

.child {
  text-align: center;
  width: 4rem;
  background-color: #ccc;
  float: left;
  margin: 0.5rem;
  height: 2rem;
  line-height: 3.125rem; }

.parent {
  background-color: #00f; }

.clearfix::after {
  content: ' ';
  display: block;
  clear: both; }
